#include <stdio.h>
#include <stdbool.h>
#include <limits.h>
/* 位字段符号常量 */

/* 边框线样式*/
#define SOLID  0
#define DOTTED 1
#define DASHED 2

//三原色
#define BLUE   4
#define GREEN  2
#define RED    1

//混合色
#define BLACK    0
#define YELLOW   (RED | GREEN)
#define MAGENTA  (RED | BLUE)
#define CYAN     (GREEN | BLUE)
#define WHITE    (RED | GREEN | BLUE)

/* 按位方法中用到的符号常量*/
#define OPAQUE       0x1
#define FILL_BLUE    0x8
#define FILL_GREEN   0x4
#define FILL_RED     0x2
#define FILL_MASK    0xE
#define BORDER       0x100
#define BORDER_BLUE  0x800
#define BORDER_GREEN 0x400
#define BORDER_RED   0x200
#define BORDER_MASK  0xE00
#define B_SOLID      0
#define B_DOTTED     0X1000
#define B_DASHED     0x2000
#define STYLE_MASK   0x3000

const char *colors[8] = {"black", "red", "green", "yellow", "blue", "magenta", "cyan", "white"};

struct box_props {
    bool opaque                 : 1; //或者unsigned int (C99以前)
    unsigned int fill_color     : 3;
    unsigned int                : 4;
    bool show_border            : 1;//或者unsigned int (C99以前 )
    unsigned int border_color   : 3;
    unsigned int border_style   : 2;
    unsigned int                : 2;

};

union Views //把数据看成结构或者unsigned short类型的变量
{
    struct box_props st_view;
    unsigned short us_view;
};

void show_settings(const struct box_props *pb);

void show_settings1(unsigned short);

char *itobs(int n, char *ps);

int main() {
    //创建Views联合,并初始化initialize struct box view
    union Views box = {{true, YELLOW, true, GREEN, DASHED}};
    char bin_str[8 *sizeof (unsigned int )+1];

    printf("Original box settings:\n");
    show_settings(&box.st_view);
    printf("\nBox settings using unsigned int view:\n");
    show_settings1(box.us_view);

    printf("bits are %s \n", itobs(box.us_view,bin_str));

    box.us_view &= ~FILL_MASK;
    box.us_view |= (FILL_BLUE | FILL_GREEN);
    box.us_view ^= OPAQUE;
    box.us_view |= BORDER_RED;
    box.us_view &= ~STYLE_MASK;
    box.us_view |= B_DOTTED;
    printf("\nModified box settings:\n");
    show_settings(&box.st_view);
    printf("\nBox settings using unsigned int view:\n");
    show_settings1(box.us_view);
    printf("bits are %s\n", itobs(box.us_view,bin_str));

    return 0;
}

void show_settings(const struct box_props *pb) {
    printf("Box is %s.\n", pb->opaque == true ? "opaque" : "transparent");
    printf("The fill color is %s.\n", colors[pb->fill_color]);
    printf("Border %s.\n", pb->show_border == true ? "shown" : "not shown");
    printf("The border color is %s.\n",colors[pb->border_color]);
    printf("The border style is ");
    switch (pb->border_style) {
        case SOLID:
            printf("solid.\n");
            break;
        case DOTTED:
            printf("dotted.\n");
            break;
        case DASHED:
            printf("dashed.\n");
            break;
        default:
            printf("unknown type.\n");
    }

}

void show_settings1(unsigned short us) {
    printf("box is %s.\n", (us & OPAQUE) == OPAQUE ? "opaque" : "transparent");
    printf("The fill color is %s.\n", colors[(us >> 1) & 07]);
    printf("Border %s.\n", (us & BORDER) == BORDER ? "shown" : "not shown");
    printf("The border style is ");
    switch (us & STYLE_MASK) {
        case B_SOLID:
            printf("solid.\n");
            break;
        case B_DOTTED:
            printf("dotted.\n");
            break;
        case B_DASHED:
            printf("dashed.\n");
            break;
        default:
            printf("unknown type.\n");
    }
    printf("The border color is %s.\n", colors[(us >> 9) & 07]);
}

char *itobs(int n, char *ps) {
    int i;
    const static int size = CHAR_BIT * sizeof(int);

    for (i = size - 1; i >= 0; i--, n >>= 1)
        ps[i] = (01 & n) + '0';
    ps[size] = '0';

    return ps;
}